Confirmation on diagnosis

[buzzard103]

my 2001 f350 has been hard to start on cool mornings( below 50). Once it starts in the morning its fine even after sitting all day. The starter would drag in the mornings. I would turn the key on and the voltage would drop to 10 volts wait for the gp to warm up and the volts went to 12 volts try to start. hold key to start for 5 seconds no crank try again this could happen no more than three times then batteries to dead to start. I took the negative battery cable off the passenger side and my little hood light went off no power. Does this mean the other battery is bad. i replaced the batteries in March with Napa legend 75's. all help is greatly appreciated. just curious what battery's do yall run

[GAS]

Sounds like the leads to/from the driver side battery have a problem.
Both sides have grounds to the frame and the block.

[jesilvas]

I agree. They are in parallel so even if you DC the ground on one the other one should still be grounded. Check all the battery/starter connections for tight and CLEAN connections.
What are the CCAs on the batts?
Also, I'd check your GPR and GPs once you solve the battery connection issue.
I've got Duralast Golds with a 3yr free warranty. They'll probably go out before that 3yr so free batts for life most of the time. Fine with me, I'd rather keep them fairly new like that.

[buzzard103]

the batts i have are 850 cca. when i reconnected the driver side and unconnected the passenger the light stayed on so ithought that would mean the passenger batt was bad or dead cell

[jesilvas]

Not necessarily. Test the voltage on both individually to see if they are ok.
Also, check continuity between each lead on the battery wires to see if there is a break in them.

[buzzard103]

how do check the continuity in the cables

[jesilvas]

Multi meter. Set it to ohms, which is resistance. While testing the battery cable ONLY (as in d/c from the batteries) you put one lead to one battery cable connection and the other lead to the other connection for hot and ground just to check them and see if there is infinite resistance or very little. Infinite means there is resistance of an infinite amount, and little means that there is no break in the wiring or connection.

[buzzard103]

infinite is bad and a little resistance is good, correct i've never had to use one i'm a machinist by trade parts replacer by neccessity

[jesilvas]

In this instance yep.

[buzzard103]

ok thanks for the info and patience